Biodegradable aliphatic-aromatic polyesters

Abstract

Biodegradable aliphatic/aromatic copolyester comprising 50 to 60 mol % of an aromatic dicarboxylic acid and 40 to 50 mol % of an aliphatic acid, at least 90% of which is a long-chain dicarboxylic acid (LCDA) of natural origin selected from azelaic acid, sebacic acid, brassylic acid or mixtures thereof; and a diol component.

1. Biodegradable aliphatic/aromatic copolyester (AAPE) comprising:
 A) an acid component comprising repeating units of: 
 1) 50 to 60 mol % of an aromatic polyfunctional acid; 
 2) 40 to 50 mol % of an aliphatic acid, at least 90% of which is a long-chain dicarboxylic acid (LCDA) of natural origin selected from azelaic acid, sebacic acid, brassylic acid or mixtures thereof; 
 B) at least one diol component; said aliphatic long-chain dicarboxylic acid (LCDA) and said diol component (B) having a number of carbon atoms according to the following formula: (C LCDA ·Y LCDA )/2+C B  Y B >7.5 where: 
 C LCDA  is the number of carbon atoms of the LCDA and can be 9, 10 or 13; 
 Y LCDA  is the molar fraction of each LCDA on the total number of moles of LCDA; 
 C B  is the number of carbon atoms of each diol component; 
 Y B  is the molar fraction of each diol on the total number of moles of the diol component (B) said AAPE having: a biodegradability after 90 days higher than 70%, with respect to pure cellulose according to the Standard ISO 14855Amendment 1, 
 a density of equal to or less than 1.2 g/cc; 
 a number average molecular weight of 40,000-140,000; 
 an inherent viscosity of 0.8-1.5. 
 
     
     
       2. Biodegradable polyester according to  claim 1 , wherein said aromatic dicarboxylic acid is selected from the group consisting of the phthalic acids. 
     
     
       3. Biodegradable polyester according to  claim 2 , wherein said aromatic dicarboxylic acid is terephthalic acid. 
     
     
       4. Biodegradable polyester according to  claim 1 , wherein the polydispersity index M w /M n , is between 1.7 and 2.6. 
     
     
       5. Biodegradable polyester according to  claim 4 , wherein said polydispersity index M w /M n  is between 1.8 and 2.5. 
     
     
       6. Biodegradable polyester according to  claim 1 , wherein said diol is selected from the group consisting of: 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,4-cyclohexanedimethanol, propylene glycol, neo-pentyl glycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, and cyclohexanemethanediol. 
     
     
       7. Biodegradable polyester according to  claim 1 , wherein said diol has from 2 to 10 carbon atoms. 
     
     
       8. Biodegradable polyester according to  claim 7 , wherein said diol has from 2 to 4 carbon atoms. 
     
     
       9. Biodegradable polyester according to  claim 1 , characterized in that said aliphatic long-chain dicarboxylic acid (LCDA) and said diol component (B) have a number of carbon atoms according to the following formula:
   ( C   LCDA   ·Y   LCDA )/2 +C   B   ·Y   B >8. 
 
     
     
       10. Biodegradable polyester according to  claim 1 , wherein said biodegradability after 90 days is higher than 80%. 
     
     
       11. Biodegradable polyester according to  claim 1 , having a crystallization temperature T c  higher than 25° C. 
     
     
       12. Biodegradable polyester according to  claim 11 , having a crystallization temperature T c  higher than 30° C. 
     
     
       13. Biodegradable polyester according to  claim 12 , having a crystallization temperature T c  higher than 40° C. 
     
     
       14. Biodegradable polyester according to  claim 1 , wherein said aliphatic acid comprises at least one hydroxy acid in an amount of up to 10 mol % with respect to the total molar content of the aliphatic acid. 
     
     
       15. A film comprising the polyesters according to  claim 1 .